Safety switch plate



Oct. 1, 1935. F. E. 'nFl-ANY 2,015,698

SAFETY SWITCH PLATE Filed Dec. 7, 1935 4 nlm Patented Oct. 1, 1935 UNITED STATES PATENT OFFICE SAFETY SWITCH PLATE Application December 7, 1,933, Serial No. 702,310

4 Claims.

5 of my safety switch plate.

The object of my invention is to determine, by sight in a dark room, the location of electric light switches and of electric switches of any other kind so as to guide persons entering the room to the position of said electric switches.

A further object of my invention is to indicate whether such electrical switches located either in the same room with the safety switch plate or in an independent and different place, are in their open or closed position, thereby the safey switch plate serving as a checking device upon electrical circuits.

Referring to the accompanying drawing my invention may be exemplified by the following description and exhibition.

Fig. l shows my safety switch plate in front elevation. Fig. 2 is a longitudinal cross section or" Fig. l. Fig. 3 is a back view of Fig. 1. Fig. i demonstrates the operation of the device by means of a circuit diagram.

In the drawing i is the body of the safety switch plate made of any suitable material. 2 is a hole through the plate I and acts as a window for the indicator device 6 which is, in this example, located within a semicylindrical protuberance 3 carried by the plate I. The body of the switch plate may be `fixed to walls and building frames by means of screws inserted through screw holes- 4. This provision renders the invention t and applicable in place of any standard electric wall switch plates presently in use and provides for a quick replacement of standard switch plates by my safety switch plate, without any essential change in the wiring. The switch handle itself protrudes, for operability, through handle hole 5.

Behind opening 2 is a transparent or translucent plate 'I following the semi-cylindrical shape of the opening and being placed between the opening and the indicator device E. 1 may be colored.

As an integral part of the switch plate, indicator device 6 is immovably fixed within the semicylindrical protuberance 3 of the plate I. The indicator device consists of a gas bulb containing any suitable gas at low pressure and also containing two electrodes, shown at I5 in Fig. 4, which electrodes terminate, through exible leads 8 and 9, that may be easily and quickly attached to terminals Ill, of the switch circuit. When so attached a shunt circuit will be established around (Cl. 20D-167) the switch II from its terminal I0 in which the gaseous bulb 6 is included.

The operation of the device is as follows: As shown in Fig. 4, the indicator bulb is shunted across the switch terminals of any electrical switch 5 in connection with which the safety switch plate is desired to be used. This shunting is obtained by connecting the terminals I0 of bulb 6 to the switch terminals of switch II which serves to close and open an electric circuit fed from ter- 10 minals I3, across line I4 and current consumer I2 of which I6 is the consuming resistance. When switch II is in its open position, as shown in Fig.

4, the indicator bulb 6 is connected in series in circuit I3, I4, I6, 8, 6, 9, I3. The electrodes I5, 15 however, do not constitute a direct wire connection and are placed within bulb 6 in such a way that at the available potential difference existing between them they effect ionization of the gas enclosed in the bulb, thereby creating a visi- 20 ble glow which may be viewed through plate 'I and window opening 2, thus indicating that the consuming device I2, I6, which latter now acts only as a circuit resistance, is not in operation and showing, at the same time, the location of 25 the switch or @witch box.

While the switch is in its open position, as described hereinbefore, the ionization current through bulb is so low, as a result of geometrical and assembly arrangement of the bulb, that no appreciable current is consumed and the indicator may be left in this indicating position, that is with open switch, indefinitely without any expense.

At the moment switch AII is closed, the indicator bulb B is shunted by switch I I and no ionization current can develop. The indicator bulb is dark now and this is the sign of the consumer I6 being operated.

An important feature of my invention resides in the fact that my switch-plate with its gaseous light bulb may be sold as a complete unit to be substituted for existing switch-plates without necessitating a change in the installed wiring circuits. This is made possible from the fact 45 that the flexible leads connected with the electrodes of the gaseous bulbof my invention are of suicient length to permit them to be attached to the circuit terminals IIJ of the switch II, shown in Fig. 4. When so connected the 50 gaseous bulb 6, will be included in a shunt circuit leading around the switch terminals I0. Therefore when the switch II, is moved across the terminals I0, to complete the main circuit through the house lights I2, the gaseous bulb 55 What I claim is:

1. A switch-plate of the character described, having an outwardly extending housing provided with a sight window and said plate having a plurality of openings through which tastening devices and a switch operating member 'may extend, the front and end walls of the housing being formed integral with the plate and located within the marginal edges thereof, and a gaseous light bulb supported within said housing in rear of its window, said bulb having its electrodes terminating in exible lead wires adapted to be readily attached to the terminals of an electric switch circuit located in rear of the said plate to provide a shunt circuit in which said gas bulb is included, the construction and arrangement being such that no part of the bulb or its lead wires projects beyond the upper edge oi' the plate.

2. In combination with an electric switch and its terminals, a. switch plate of the character described provided with an integral housing having a sight window and said plate having a plurality oi' openings through which fastening devices and a switch operating member may extend, said housing located within the marginal edges of the plate and having closed ends, and an elongated gaseous 'light bulb positioned in said housing in rear of said window, the current lead wires for the bulb electrodes extending. lthrough the opposite ends of the bulb vmld Bald y having its estabiishashuntcircuitinwhichthegasbulb wires extends beyond the upper edge o! the plate, whereby said edge may make contact with the wall to which the plate is attached. 10

3. In combination with a switch plate having an integral outwardly protruding wall constituting a light bulb housing provided with a window opening and said plate having other openings to receive plate securing means and a switch l5 operating member, the walls oi' the housing located within the marginal edges oi.' the plate, a gaseous light bulb shaped to be positioned in the housing formed by said protruding wall and in rear of the window opening, said light bulb 20 electrode lead wires extending from' the opposite ends thereof and terminating in flexible l the ends ot which are adapted to be connected to the terminals of a switch circuit located in rear oi' the switch plate, thus 25 establishinga shunt circuit from said terminals in which the gaseous bulb is included, the construction and arrangement being such that the bulb and its lead wires will be entirely covered by the plate proper and its housing with no por- I0 tion thereof extending beyond the upper edge ot the plate.

4. A switch plate of the character described, having an integral outwardly extending wall protruding from its front face and all portions It!4 of which are located within the marginal edges of the plate, said wall having a sight window and the plate having a plurality oi openings through which plate-fastening devices and a switch operating member may extend, said pro- 40 y truding wall providing a housing open at the rear of the plate and oi' less length than the width o! the plate. said housing constructed to receive, house and support a gaseous light bulb.

FRANK EMERY TIFFANY. 

